To successfully increase Californians’ reliance on electric vehicles over the next decade without overloading the state’s electric grid, more drivers will need to charge their cars during the day, a Stanford study has found.
According to the study, published this week in the journal Nature Energy, the state needs to dramatically increase and improve public and workplace charging infrastructure that supports daytime charging and can make better use of solar energy. According to the study, the increased charging availability will also make owning electric vehicles more accessible.
“If we pay a lot of attention to building a large public charging network wherever people are during the day — at work, in public places… it will be a big win for the network,” said Siobhan Powell, the lead researcher of the to learn.
The study, part of Stanford’s Bits & Watts initiative, which brings together researchers with energy industry leaders, used modeling to forecast EV charging needs in 2035 in 11 western states, including California. The team predicted that both EV use and reliance on renewable energy will increase over the next 13 years, noting that improvements in public charging infrastructure — reducing reliance on nighttime power supplies — could ensure that plug-in -Vehicles have the least impact on the power grid.
EV owners are likely to be in high income brackets and charge their batteries overnight at home – often taking advantage of incentives offered by energy suppliers to do so. If these charging habits persist as EV use surges, peak electricity demand could increase by up to 25%, the researchers found.
While a switch to more stores a day isn’t expected to stem the surge in demand, it would delay the peak if California has a history of grid overcapacity thanks to solar power. This shift could also help the West prepare for high stress on its power system during heatwaves that continue to push the grid to its limits.
By 2035, when California commits to ending sales of new fossil-fuel vehicles, increased capacity will make solar power cheaper during the day, according to Ram Rajagopal, study co-author and associate professor of civil and environmental engineering and electrical engineering at Stanford.
“Charging in the workplace, in particular, is a very good fit for solar energy,” Powell added.
Increasing the number of stations that support daytime charging would “improve the impact of EV charging, support equitable widespread adoption, reduce emissions, support renewable energy integration and facilitate the transition to a decarbonized future,” according to the study.
“Increasing the number of public charging stations per day will benefit the grid, but it can also help give more people access to charging,” Powell said.
She concedes that the state needs “more millions” charging stations to meet its goal of having 5 million zero-emission vehicles on the road by 2030 – almost five times the current amount. But she hopes the research can help shape policy about how and where the stations will be implemented.
The findings don’t mean people should stop charging EVs at home and overnight when it works best for them, Powell said, because the priority should be to encourage the use of lower-emission or zero-emission vehicles. However, she would like the study to influence policymakers or companies that build charging stations. That way, “it can be a convenient choice for people to charge at a time when it’s better for the grid,” Powell said.
Rajagopal, who is director of Stanford Sustainable Systems Labs, said it could help if people got into the habit of charging during the day.
“If we get people used to the right behavior now, then by the time this transition is complete, we will already be doing the right thing,” he said.
https://www.latimes.com/california/story/2022-09-24/california-electric-vehicles-daytime-charging-power-grid-study Charging electric cars during day could help grid, study says